excuse for the practice when the supply of a certain varnish runs out, but ordinarily it is entirely against common sense. Varnishes are made for so great a variety of purposes that there is no necessity to mix two together. A moment's reasoning will make it clear that if two varnishes mixed together would give a better result than either one used separately, that the varnish manufacturers themselves would make such a mixture before sending the varnish out. It is quite possible that the ingredients from which the varnish are made would react detrimentally one on the other. It is therefore strongly advisable for the painter not to mix varnishes under any circumstances.
The second objectionable practice alluded to is that of thinning the varnish by adding linseed oil to it; in cold weather varnish sometimes pulls, that is, it is so thick that it is a little difficult to apply without considerable strain on the wrist. In such eases the workman will sometimes add the oil, which may not show up at the time, but it is sure to eventually prove disastrous. Cases have been known where the painter, to save himself trouble, has smuggled in a small bottle of linseed oil, and has added it surreptitiously to the varnish, and caused a great deal of complaint to the manufacturers. In the above remarks only turpentine and oil varnishes have been referred to, not spirit varnish. This, however, is almost invariably mixed with stain as far as the painter's use is concerned. Under the head of Staining will be found information on this subject.
Varnishing can only be properly done by means of brushes specially made for the purpose. There is a very useful grade of varnish made which is known as rubbing varnish. This is applied in the ordinary way, and is, when dry, rubbed down with felt and water dipped in powdered pumice stone. Several coats are usually given, each being rubbed down.
